How to fix Dispatcher publish connectivity issue?

Issue

While configuring dispatcher with AEM on any web server the connectivity does not work. Even though the publish is accessible successfully from http clients like browser, curl... from dispatcher box.

Symptoms

You see one of the following messages in the dispatcher logs file:

• No correct backend found in farm
• Permission denied...

Solution

Discuss with the security team to allow restrictions in firewall settings. Below are some of the hints on the Linux box to verify in case you have access rights. 

• Iptables is a standard firewall included in most Linux distributions by default to block unwanted traffic. Turn it off & verify. The command is 

/etc/init.d/iptables stop

• By default, SELinux does not allow Apache to make socket connections. The command to allow is 

setsebool -P httpd_can_network_connect 1

Note: The above command is to quickly verify but discuss with the network security team & they will help to configure properly per organization security rules.